Too much for flow for a 90?

[geforce]

Hey all, I recently got a awesome deal on two mp40's giving me a total of 4 now for my 90 gallon. My question is should I sell the 4th one because 4 mp40's is overkill for a 90? or should I add the 4th one to the current setup.

I currently have it so theres 1 mp40 on each side of the tank and the third mp40 center backglass and dialed down to 50%.

Currently I dont notice anymore dead spots but debating if I should sell or not.

Input guys?